Toward Dynamic Interoperability of Mobile Agent Systems

Mobile agents are an increasingly popular paradigm and in recent years there has been a proliferation of mobile-agent systems. These systems are, however, largely incompatible with each other. In particular, agents cannot migrate to a host that runs a different mobile-agent system. Prior approaches to interoperability have tried to force agents to use a common API and so far none have succeeded. This goal led to our efforts to develop mechanisms that support dynamic runtime interoperability of mobile-agent systems. This paper describes the \em Grid Mobile-Agent System, which allows agents to migrate to different mobile-agent systems

Lease-based Decentralized Resource Management in Open Multi-Agent Systems

A distributed management architecture is proposed for Internet-scale, open, distributed agent middleware systems. The management architecture presented supports the autonomy of both agents and middleware resources, incorporating an agent-initiated contract negotiation model for resource allocation and access. A leasing mechanism infrastructure designed and implemented for this purpose is presented

Heterogeneous Strong Computation Migration

The continuous increase in performance requirements, for both scientific computation and industry, motivates the need of a powerful computing infrastructure. The Grid appeared as a solution for inexpensive execution of heavy applications in a parallel and distributed manner. It allows combining resources independently of their physical location and architecture to form a global resource pool available to all grid users. However, grid environments are highly unstable and unpredictable. Adaptability is a crucial issue in this context, in order to guarantee an appropriate quality of service to users. Migration is a technique frequently used for achieving adaptation. The objective of this report is to survey the problem of strong migration in heterogeneous environments like the grids', the related implementation issues and the current solutions.Comment: This is the pre-peer reviewed version of the following article: Milan\'es, A., Rodriguez, N. and Schulze, B. (2008), State of the art in heterogeneous strong migration of computations. Concurrency and Computation: Practice and Experience, 20: 1485-1508, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/cpe.1287/abstrac

Reification of network resource control in multi-agent systems

In multi-agent systems [1], coordinated resource sharing is indispensable for a set of autonomous agents, which are running in the same execution space, to accomplish their computational objectives. This research presents a new approach to network resource control in multi-agent systems, based on the CyberOrgs [2] model. This approach aims to offer a mechanism to reify network resource control in multi-agent systems and to realize this mechanism in a prototype system. In order to achieve these objectives, a uniform abstraction vLink (Virtual Link) is introduced to represent network resource, and based on this abstraction, a coherent mechanism of vLink creation, allocation and consumption is developed. This mechanism is enforced in the network by applying a fine-grained flow-based scheduling scheme. In addition, concerns of computations are separated from those of resources required to complete them, which simplifies engineering of network resource control. Thus, application programmers are enabled to focus on their application development and separately declaring resource request and defining resource control policies for their applications in a simplified way. Furthermore, network resource is bounded to computations and controlled in a hierarchy to coordinate network resource usage. A computation and its sub-computations are not allowed to consume resources beyond their resource boundary. However, resources can be traded between different boundaries. In this thesis, the design and implementation of a prototype system is described as well. The prototype system is a middleware system architecture, which can be used to build systems supporting network resource control. This architecture has a layered structure and aims to achieve three goals: (1) providing an interface for programmers to express resource requests for applications and define their resource control policies; (2) specializing the CyberOrgs model to control network resource; and (3) providing carefully designed mechanisms for routing, link sharing and packet scheduling to enforce required resource allocation in the network

Technology Portfolios: A Metaphor For Usersʼ Technology Selections While Mobile?

Humans employ metaphors to understand, communicate and appropriate new, complex or perplexing aspects of their lives. This paper suggests that the rapid diffusion and widespread acceptance of mobile technologies have not been accompanied by a rich set of metaphors. Apt metaphors might help us to make sense of these technologies and the new practices that are emerging around them. The metaphor of a technology portfolio is proposed for users\u27 selections and deployment of technologies while mobile. Three case studies examining users’ technology selections while mobile are described. Observed practices can be understood and explained using the technology portfolio metaphor. The metaphor is particularly valuable given the changing nature of mobile technologies and the resulting difficulties in envisioning likely future needs and practice

Making Friends in the Rainforest: Negrito Adaptation to Risk and Uncertainty

The so-called negritos adapt not just to a tropical forest environment but also to an environment characterized by perturbations and fluctuations. As with other hunter-gatherers in the region and, indeed, throughout the world, they use both social and ecological methods to enhance their chances of survival in this changing environment: socially, they have developed networks of trading and marriage partners; ecologically, they maintain patches of key resources that are available for future harvesting. As evidenced in the case of the Batek (Orang Asli), patterns of forest structure and composition are sometimes direct outcomes of intentional resource concentration and enrichment strategies. While little of the above is controversial anthropologically, what has drawn some debate is the nature of the relationship with partner societies. Conventional wisdom posits relations of inequality between foragers and others : foragers and farmers are often construed as hierarchical dyads where foragers supply products or labor to farmers in exchange for agricultural harvests and other trade goods. This kind of adaptation appears to be one of divergent specialization. However, there are cases, such as in the relationship between Batek and Semaq Beri, where both societies follow a roughly similar mode of adaptation, and specialization has not materialized. In sum, while not denying that hierarchy and inequality exist, I suggest that they have to be contextualized within a larger strand of relationships that includes both hierarchy and egality. Further, such relationships are part of the general portfolio of risk reduction strategies, following which access to widely scattered environmental resources, and passage from one location to another, is enhanced not by competing with and displacing neighbors but by maintaining a flexible regime of friendly exchange partners